U.S. patent application number 13/417988 was filed with the patent office on 2012-08-16 for method for accessing hybrid network, and gateway apparatus, wireless terminal and communication system thereof.
Invention is credited to Yong Bai, Lan Chen, Lei Du, Hidetoshi Kayama.
Application Number | 20120207049 13/417988 |
Document ID | / |
Family ID | 37714639 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120207049 |
Kind Code |
A1 |
Du; Lei ; et al. |
August 16, 2012 |
METHOD FOR ACCESSING HYBRID NETWORK, AND GATEWAY APPARATUS,
WIRELESS TERMINAL AND COMMUNICATION SYSTEM THEREOF
Abstract
A method for accessing a hybrid network and a gateway
communication system are disclosed. The method comprises: sensing
by a gateway apparatus a relay request slot on a downlink common
control channel of the wide area network; transmitting by a
wireless terminal a relay request signal requesting to relay a data
packet to be transmitted, in the relay request slot on the downlink
common control channel; and if the relay request signal from the
wireless terminal is sensed in the relay request slot, establishing
by the gateway apparatus a connection with the wireless terminal in
a distributed network environment. As such, the gateway apparatus
accesses the wireless distributed network only when the surrounding
wireless terminals require data relay, without sensing signals on
both networks simultaneously.
Inventors: |
Du; Lei; (Beijing, CN)
; Bai; Yong; (Beijing, CN) ; Chen; Lan;
(Beijing, CN) ; Kayama; Hidetoshi; (Beijing,
CN) |
Family ID: |
37714639 |
Appl. No.: |
13/417988 |
Filed: |
March 12, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12563865 |
Sep 21, 2009 |
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13417988 |
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11583651 |
Oct 18, 2006 |
8160048 |
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12563865 |
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Current U.S.
Class: |
370/252 ;
370/315 |
Current CPC
Class: |
H04W 48/14 20130101;
H04W 48/16 20130101; Y02D 70/142 20180101; H04W 84/12 20130101;
Y02D 70/22 20180101; H04W 48/12 20130101; H04W 88/04 20130101; Y02D
70/144 20180101; H04W 84/042 20130101; Y02D 30/70 20200801; H04W
88/06 20130101 |
Class at
Publication: |
370/252 ;
370/315 |
International
Class: |
H04L 12/26 20060101
H04L012/26; H04B 7/14 20060101 H04B007/14 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 19, 2005 |
CN |
200510109212.4 |
Claims
1. A method for establishing a wireless connection at a gateway
apparatus which communicates with a base station in a wireless Wide
Area Network (WAN), the method comprising the steps of: sensing a
downlink common control channel of the WAN to determine whether the
downlink common control channel has a relay request slot; receiving
a relay request message requesting to relay a data packet, in the
relay request slot on the downlink common control channel, in case
that the downlink common control channel has the relay request
slot; and establishing a wireless connection with the wireless
terminal in a wireless distributed network in response to the relay
request message.
2. The method according to claim 1, wherein the step of
establishing a wireless connection with the wireless terminal
comprises: transmitting a reply message to the wireless terminal
after receiving the relay request message; receiving a selection
message transmitted by the wireless terminal, the selection message
contains an address of the gateway apparatus through which the
relay operation is to be made; and in response to the selection
message, transmitting to the wireless terminal a permit message to
permit the wireless terminal transmitting the data packet to be
relayed.
3. The method according to claim 1, further comprising a step of:
transmitting the reply message to the wireless terminal in the
wireless distributed network once detecting that a power level on
the relay request slot is larger than a noise power.
4. The method according to claim 1, further comprising a step of:
transmitting the reply message to the wireless terminal in the
wireless distributed network, once detecting a high level on the
relay request slot.
5. The method according to claim 1, wherein the gateway apparatus
performs data packet transmissions with multiple wireless terminals
around in a polling manner.
6. A method for establishing a wireless connection at a wireless
terminal, the method comprising the steps of: sensing a downlink
common control channel of a wireless Wide Area Network (WAN) to
determine whether the downlink common control channel has a relay
request slot; transmitting a relay request message requesting to
relay a data packet, in the relay request slot on the downlink
common control channel, in case that the downlink common control
channel has the relay request slot; and receiving a reply message
on a wireless distributed channel transmitted by the gateway
apparatus which communicates with a base station of the WAN; and
establishing a wireless connection with the gateway apparatus in a
wireless distributed network in response to the reply message.
7. The method according to claim 6, further comprising the steps
of: determining the gateway apparatus through which a relay
operation is to be made by measuring conditions of channels; and
transmitting a selection message which contains an address of the
gateway apparatus through which the relay operation is to be
made.
8. The method according to claim 6, wherein the wireless terminal
compares conditions of channels indicated in the reply message, and
selects a gateway apparatus with the best condition of channel as
the gateway apparatus through which the relay operation is to be
made.
9. The method according to claim 6, wherein the wireless terminal
selects a gateway apparatus that needs the lowest transmission
power for directly communicating therewith as the gateway apparatus
through which the relay operation is to be made.
10. The method according to claim 6, wherein the wireless terminal
selects a gateway apparatus with the highest signal to interference
and noise ratio (SINR) as the gateway apparatus through which the
relay operation is to be made.
11. The method according to claim 6, wherein the wireless terminal
selects the nearest gateway apparatus as the gateway apparatus
though which the relay operation is to be made.
12. A gateway apparatus which communicates with a base station in a
wireless Wide Area network (WAN), comprising: a wireless wide area
network transceiving unit configured to transmit and receive
messages in the wireless wide area network; a wireless distributed
network transceiving unit configured to transmit and receive
messages in a wireless distributed network; a detection unit
configured to detect the messages received by the wireless wide
area network transceiving unit on a downlink common control channel
of the WAN, and determine whether the downlink common control
channel has a relay request slot; an access determination unit
configured to determine that a wireless terminal needs to access
the wireless distributed network in case that the detection unit
detects a relay request slot and a relay request message is
received on the relay request slot; and a transmission control unit
configured to instruct the wireless distributed network
transceiving unit to transmit a reply message to establish a
wireless connection with the wireless terminal in the wireless
distributed network.
13. The gateway apparatus according to claim 12, wherein the
wireless distributed network transceiving unit is further
configured to transmit a reply message to the wireless terminal
after receiving the relay request message, receive a selection
message transmitted by the wireless terminal and containing an
address of the gateway apparatus through which the relay operation
is to be made, and transmit to the wireless terminal a permit
message to permit the wireless terminal transmitting the data
packet to be relayed in response to the selection message.
14. The gateway apparatus according to claim 12, wherein the
wireless distributed network transceiving unit is further
configured to transmit the reply message to the wireless terminal
in the wireless distributed network, once the detection unit
detects that a power level on the relay request slot is larger than
a noise power.
15. The gateway apparatus according to claim 12, wherein the
wireless distributed network transceiving unit is further
configured to transmit the reply message to the wireless terminal
in the wireless distributed network, once the detection unit
detects a high level on the relay request slot.
16. The gateway apparatus according to claim 12, wherein the
gateway apparatus performs data packet transmissions with multiple
wireless terminals around in a polling manner.
17. A wireless terminal comprising: a wireless distributed network
transceiving unit configured to transmit and receive messages in a
wireless distributed network; a downlink common control channel
transceiving unit configured to transmit a relay request message
requesting to relay a data packet and receive messages on a
downlink common control channel of a wireless wide area network
(WAN); a detection unit configured to detect the messages received
by the downlink common control channel transceiving unit on the
downlink common control channel, and determine whether the downlink
common control channel has a relay request slot; and an access
determination unit configured to instruct the wireless terminal to
access the wireless distributed network in case that the detection
unit detects a relay request slot and a data packet is to be
relayed; and a transmission control unit configured to instruct the
downlink common control channel transceiving unit to transmit a
relay request message requesting to relay a data packet, instruct
the wireless distributed network transceiving unit to receive on
the wireless distributed channel a reply message which is
transmitted by a gateway apparatus which communicate with a base
station in a wireless wide area network, and establish a wireless
connection with the gateway apparatus in the wireless distributed
network.
18. The wireless terminal according to claim 17, wherein the
detection unit is further configured to determine the gateway
apparatus through which a relay operation is to be made by
measuring conditions of channels, and the wireless distributed
network transceiving unit is further configured to transmit a
selection message which contains an address of the gateway
apparatus through which the relay operation is to be made.
19. The wireless terminal according to claim 17, wherein the
wireless terminal compares conditions of channels indicated in the
reply message, and selects a gateway apparatus with the best
condition of channel as the gateway apparatus through which the
relay operation is to be made.
20. The wireless terminal according to claim 17, wherein the
wireless terminal selects a gateway apparatus that needs the lowest
transmission power for directly communicating therewith as the
gateway apparatus through which the relay operation is to be
made.
21. The wireless terminal according to claim 17, wherein the
wireless terminal selects a gateway apparatus with the highest
signal to interference and noise ratio as the gateway apparatus
through which the relay operation is to be made.
22. The wireless terminal according to claim 17, wherein the
wireless terminal selects the nearest gateway apparatus as the
gateway apparatus though which the relay operation is to be made.
Description
PRIORITY
[0001] This is a divisional application of U.S. Ser. No.
12/563,865, filed Sep. 21, 2009, which is a divisional of U.S. Ser.
No. 11/583,651, filed Oct. 18, 2006 (pending), which claims
priority to and incorporates by reference the entire contents of
Chinese priority document 200510109212.4, filed in China on Oct.
19, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to accessing to a hybrid
network, and more particularly, to a method for accessing multiple
networks of a hybrid network with reduced power consumption, which
reduces the time consumption of a gateway node in the idle state
for simultaneously sensing two networks while ensuring different
network signals from the hybrid network are simultaneously
received, so that power consumption per unit time of the gateway
node is reduced, and the standby or serving time of the gateway
node is increased, and gateway apparatus, wireless terminal and
communication system thereof.
[0004] 2. Description of the Prior Art
[0005] With the popularity of wireless portable terminals and the
development of communication services in various fields, the future
mobile communication system is required to perform communication in
a "ubiquitous" manner, that is, an effective wireless transmission
should be ensured anytime and anywhere. However, in the
conventional cellular network, the communications between mobile
terminals must be transferred by aid of base stations and (or)
mobile switches, which makes the communication manner be limited by
various factors such as geographical regions. For this, the
wireless distributed network independent from fixed network
infrastructure is proposed as a flexible wireless access manner, is
considered as a supplement to and as a development of the fixed
networks, and thus makes the "ubiquitous" communication manner
possible. In such an extended network environment, research about
communication techniques will not be limited only to any individual
network, and the coexistence between the hybrid networks and the
access methods of the wireless terminal in the hybrid network also
become one of the most concerned subjects.
[0006] The appearance of the wireless distributed networks, such as
Wireless Local Area Network (WLAN), Ad hoc and Bluetooth, makes the
constitution of a hybrid network more flexible. On the basis of the
architecture of a wide area cellular network, these distributed
networks provide broader network coverage, increase the system
capacity, and especially solve the wireless communication problems
by supporting direct communications among nodes in some scenarios,
such as the hotspot areas with heavy communication loads,
blind-spot areas in which a central controller of the wide area
cellular network cannot be directly reached, and a case where a
wireless terminal has insufficient power to maintain a
long-distance communication. However, since different networks
employ different communication protocols, the conventional wireless
terminal or node can only support transmissions in one network. For
this, how to support simultaneous communication with multiple
networks in the hybrid network without influences on the
transmission performance of each network is a problem to be solved
when extending the medium access method to the hybrid networks.
[0007] The most direct method for accessing multiple networks of a
hybrid network is to employ a dual-mode wireless terminal. The
dual-mode wireless terminal has a function of supporting two
communication protocols, which can flexibly select a network to be
accessed according to network conditions. For example, Reference 1
(CN 1604686, Apparatus and Method for Selecting Access Network in
Hybrid System, Sep. 27, 2004, Samsung Electronics Co., Ltd.)
proposes that a wireless terminal determines the network to be
connected according to a predetermined priority list, and when that
network fails to be connected, attempts to access a network with a
next lower priority.
[0008] Similarly, Reference 2 (GB 2269723) proposes a mobile
wireless phone supporting both cellular and local cordless system.
Firstly, a call is routed to the cordless phone through the
cordless network. Only when the position of the mobile phone cannot
be determined, the cellular and the cordless system are then
connected through the cellular network. Although the wireless
terminals in the above systems support transmissions in more than
one network, they only maintain the connection with one network at
any time and thus cannot receive signals from another network. For
example, in Reference 1, once the terminal can successfully access
to the network with the highest priority, it will maintain the
connection with the network without considering signals from other
networks, so that calls from other networks cannot reach the
wireless terminal. Therefore, a true dual-mode wireless terminal
needs to have a capability of simultaneously receiving signals from
two networks. Reference 3
(http://china.nikkeibp.co.jp/china/news/tel/tel200407190109.html)
discloses that FOMA/WLAN N900iL manufactured by NEC Corporation of
Japan can support a wireless terminal simultaneously operating on
hybrid networks. The user may switch the operation mode among
single FOMA network, single wireless local area network and
dual-mode. As shown in FIG. 1, FOMA provides wide area coverage
based on WCDMA technology. WLAN fulfills requirements of hotspot
areas or high-speed transmissions through an Access Point (AP). The
wireless terminal may simultaneously receive signals from two
networks by operating in a dual-mode. However, since the terminal
in the dual-mode needs to detect signals of two networks
simultaneously, it requires large power consumption and thus the
standby time of the terminal is shortened. For example, N900iL may
standby 280 hours when operating in single FOMA network, and may
standby up to 230 hours in single wireless local area network. If
the dual-mode is enabled, the standby time is only 150 hours.
Therefore, it is necessary to reduce the power consumption of the
terminal as much as possible in order to extend the serving time
while ensuring successful signals reception from two networks.
[0009] Though the dual-mode wireless terminal may support
communication with multiple networks, there are a number of
conventional nodes only supporting one communication protocol in
the hybrid network. Considering backward compatibility, how to make
these single-mode nodes be better served is also a problem to be
solved by the medium access control. Relay is a common access
manner, that is, a dual-mode terminal is used as a relay node. When
some conventional single-mode nodes cannot be connected to the
systems in which they have registered, the communication may be
achieved by first connecting to a surrounding dual-mode terminal
and then being forwarded by the dual-mode terminal to another
network. In this way, some nodes that would not perform
communication initially can obtain a better quality of service and
the flexibility of network extension is enhanced by the dual-mode
terminal. Reference 4 (H. Wu, C. Qiao, S. De, and O. Tonguz,
Integrated cellular and ad hoc relaying systems: iCAR, IEEE Journal
on Selected Areas in Communications, vol. 19, No. 10, October 2001)
proposes that the congestion problem of the wide area cellular
network can be solved by using Ad hoc Relaying Stations (ARS). When
resources in a cell are not enough to admit more calls, the calls
may be transferred to adjacent cells through the surrounding ARS in
order to mitigate the system congestion due to imbalanced service
distribution. However, this method requires the establishment of
the special ARS in the system which brings a large system overhead
and influences on the system flexibility. Reference 5 (Y. D. Yin,
and Y. C. Hsu, Multihop Cellular: A New Architecture for Wireless
Communications, IEEE INFOCOM, 2000) proposes that when the source
and the destination nodes are located in one cell, the system
capacity is improved by a method in which the communication is
achieved by multiple relay connections between nodes in the cell.
However, these methods all assume that all nodes in the system have
the capability of supporting communications in two networks, and
thus cannot support the conventional single-mode terminal in the
hybrid systems, and the power consumption problem of the nodes in
the system is not considered. Therefore, the present invention
relates to a hybrid network which may connect with a wide area
cellular network through a relay node (a gateway node), which while
ensuring network connectivity as much as possible, reduces power
consumption of the relay node in idle state due to simultaneously
sensing signals from two networks, in order to increase the standby
or serving time thereof.
SUMMARY OF THE INVENTION
[0010] A method for accessing a hybrid network, and a gateway
apparatus, a wireless terminal and a communication system thereof
is described. In one embodiment, a method for accessing a hybrid
network including a wide area network and a distributed network,
comprises sensing, by a gateway apparatus, a relay request slot on
a downlink common control channel of the wide area network;
transmitting, by a wireless terminal, a relay request signal
requesting to relay a data packet to be transmitted, in the relay
request slot on the downlink common control channel; and
establishing, by the gateway apparatus, a connection with the
wireless terminal in the distributed network environment, if the
relay request signal from the wireless terminal is sensed in the
relay request slot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be more clearly understood from
the description of preferred embodiments as set forth below, with
reference to the accompanying drawings, wherein:
[0012] FIG. 1 shows a schematic diagram of an existing FOMA/WLAN
dual-mode terminal in a hybrid network;
[0013] FIG. 2 shows a schematic diagram of the structure of the
hybrid network formed by a wide area cellular network and a
wireless distributed network related with the present
invention;
[0014] FIG. 3 is a schematic diagram of the downlink common control
channel of a wide area cellular network according to the first
embodiment of the present invention;
[0015] FIG. 4(a) is a block diagram of the gateway apparatus
supporting communications in two networks in the hybrid network
according to the first embodiment of the present invention;
[0016] FIG. 4(b) is a block diagram of the wireless terminal having
transmission capability in the distributed network according to the
first embodiment of the present invention;
[0017] FIG. 5 is a schematic diagram for accessing when the
wireless terminal has a transmission request in the hybrid network
of the present invention;
[0018] FIG. 6 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the first embodiment of the present
invention;
[0019] FIG. 7 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-point transmission with the wireless terminal
in the hybrid network according to the first embodiment of the
present invention;
[0020] FIG. 8 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a
point-to-point connection with the gateway apparatus and then
transmits data according to the first embodiment of the present
invention;
[0021] FIG. 9 is a timing diagram of respective nodes in a case
where the wireless terminal performs retransmission when no reply
signal is received in a reception threshold time according to the
first embodiment of the present invention;
[0022] FIG. 10 is a timing diagram of respective nodes in a case
where multiple wireless terminals transmit relay request signals in
one and the same relay request slot according the first embodiment
of the present invention;
[0023] FIG. 11 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-multipoint transmission with multiple wireless terminals
in the hybrid network according to the first embodiment of the
present invention;
[0024] FIG. 12 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-multipoint transmission with multiple wireless
terminals in the hybrid network according to the first embodiment
of the present invention;
[0025] FIG. 13 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a connection
with the gateway apparatus and then transmits data in the
point-to-multipoint scenario according to the first embodiment of
the present invention;
[0026] FIG. 14 is a timing diagram of the channels related with the
second embodiment of the present invention;
[0027] FIG. 15(a) is a block diagram of the gateway apparatus
supporting communications in two networks in the hybrid network
according to the second embodiment of the present invention;
[0028] FIG. 15(b) is a block diagram of the wireless terminal only
supporting transmissions in the distributed network in the hybrid
network according to the second embodiment of the present
invention;
[0029] FIG. 16 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the second embodiment of the present
invention;
[0030] FIG. 17 is a detail flowchart of operation on the gateway
apparatus side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the second embodiment of the present
invention;
[0031] FIG. 18 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a
point-to-point connection with the gateway apparatus and then
transmits data according to the second embodiment of the present
invention;
[0032] FIG. 19 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-multipoint transmission with multiple wireless terminals
in the hybrid network according to the second embodiment of the
present invention;
[0033] FIG. 20 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-multipoint transmission with multiple wireless
terminals in the hybrid network according to the second embodiment
of the present invention; and
[0034] FIG. 21 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a
point-to-multipoint connection with the gateway apparatus and then
transmits data according to the second embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] In another embodiment of the present invention, a wireless
terminal that performs communication through a relay of a gateway
apparatus in a hybrid network including a wide area network and a
distributed network, comprises: a distributed network transceiving
means for transmitting and receiving signals in the distributed
network; a downlink common control channel transceiving means for
transmitting a relay request signal requesting to relay a data
packet to be transmitted and receiving signals on a downlink common
control channel of the wide area network; a detection means for
detecting the signals received by the downlink common control
channel transceiving means on the downlink common control channel,
and detecting the type of current slot on the downlink common
control channel; and an access determination means for receiving
information from the detection means and determining a network to
be accessed currently.
[0036] Thus, a dedicated slot on the downlink common control
channel (DCCCH) of the wide area network is allocated for carrying
information from the wireless distributed network, so that the
gateway apparatus or the dual-mode wireless terminal functioning as
a gateway apparatus can obtain transmission requests in both
networks as long as the downlink common control channel from the
wide area cellular network is sensed in an idle standby state, and
enables the operation mode thereof when there is a transmission
request in the wireless distributed network, so that unnecessary
power consumption is saved and the serving time of the gateway
apparatus is increased.
[0037] In another embodiment of the present invention, a method for
accessing a hybrid network including a wide area network and a
distributed network, comprises: regularly transmitting by a base
station of the wide area network a synchronization signaling for
synchronizing with a downlink common control channel, on a
transmission frequency band of the wireless distributed network;
transmitting by a wireless terminal a relay request signal
requesting to relay a data packet to be transmitted, after
receiving the synchronization signaling; starting by a gateway
apparatus to access the distributed network to receive the relay
request signal from the wireless terminal at a time instant
corresponding to the synchronization signaling sensed on the
downlink common control channel; and establishing by the gateway
apparatus a connection with the wireless terminal in the
distributed network environment.
[0038] In another embodiment of the present invention, a gateway
apparatus for accessing a hybrid network including a wide area
network and a distributed network, comprises: a wide area network
transceiving means for transmitting and receiving signals in the
wide area network; a distributed network transceiving means for
transmitting and receiving signals in the distributed network; a
timer means for detecting whether current time is an integer
multiple of a periodic time, and periodically enabling a sensing
unit to sense a channel of the distributed network; and a sensing
means for sensing the channel of the distributed network at the
enabling time instant instructed by the timer means.
[0039] In another embodiment of the present invention, a wireless
terminal which performs communication through a relay of a gateway
apparatus in a hybrid network including a wide area network and a
distributed network, comprises: a distributed network transceiving
means for transmitting and receiving signals in the distributed
network; a transmission control means for controlling transmission
and reception of signals in the distributed network, and clocking;
and a delay means for receiving an instruction from the
transmission control means and delaying.
[0040] Thus, a synchronization signaling for synchronizing with the
downlink common control channel is regularly transmitted on the
transmission frequency band of the wireless distributed network by
the base station of the wide area network. After receiving the
synchronization signaling, the wireless terminal transmits the
relay request signal, and the gateway apparatus may enable the
access to the distributed network corresponding to the
synchronization signaling in order to receive the relay request
signal from the wireless terminal. Therefore, the gateway apparatus
only senses the distributed network intermittently, and thus the
power consumption is reduced, and the serving time of the gateway
node is increased.
[0041] Hereafter, the implementation of the present invention will
be described in detail by the embodiments referring to the
drawings.
[0042] Considering the above problems, embodiments of the present
invention include a method and an apparatus for accessing multiple
networks of a hybrid network with reduced power consumption.
[0043] In an embodiment of the present invention, a method for
accessing a hybrid network including a wide area network and a
distributed network, comprises: sensing, by a gateway apparatus, a
relay request slot on a downlink common control channel of the wide
area network; transmitting, by a wireless terminal, a relay request
signal requesting to relay a data packet to be transmitted, in the
relay request slot on the downlink common control channel; and if
the relay request signal from the wireless terminal is sensed in
the relay request slot, establishing, by the gateway apparatus, a
connection with the wireless terminal in the distributed network
environment.
[0044] In another embodiment of the present invention, a gateway
apparatus for accessing a hybrid network including a wide area
network and a distributed network, comprises: a wide area network
transceiving means for transmitting and receiving signals in the
wide area network; a distributed network transceiving means for
transmitting and receiving signals in the distributed network; a
detection means for detecting the signals received by the wide area
network transceiver means on a downlink common control channel of
the wide area network, and detecting the type of current slot on
the downlink common control channel; and an access determination
means for receiving results of the detection from the detection
means and determining a network to be accessed currently.
The First Embodiment
[0045] FIG. 2 shows a schematic diagram of the structure of the
hybrid network formed by a wide area cellular network and a
wireless distributed network related with the present invention. In
FIG. 2, reference sign BS denotes a base station in the wide area
cellular network, the coverage of which is shown as the bigger
ellipse, and the base station communicates with a terminal Ubi or
gateway GW within its coverage at a frequency band C. The smaller
ellipse shown in FIG. 2 denotes the coverage of the wireless
distributed network which can be various networks such as Wireless
Local Area Network (WLAN), ad hoc, or Bluetooth. This network
operates at another frequency band f1 which is not equal to the
frequency band f2, so there is no interference between the wireless
distributed network and the wide area cellular network. Reference
sign GW denotes a gateway node which is a dual-mode wireless
terminal having the capability of supporting simultaneous
communication in two networks and can successfully connect with any
one of the networks in order to provide relaying services for the
surrounding nodes. Reference sign Ubi denotes a wireless terminal
which cannot perform a communication of ensured Quality of Service
(QoS) with a central control unit of the wide area cellular network
and can be either a dual-mode terminal having the same
functionality as gateway GW but not able to communicate with the
base station (for example, located in a blind-spot area or with an
insufficient power) or a single-mode terminal only with enhanced
functionality, that is to say, only with a functionality of
supporting transmissions in the wireless distributed network and
transmitting and receiving signals on a downlink common control
channel of the wide area cellular network. In one embodiment of the
present invention, it is assumed that all the terminals including
gateway GW and wireless terminal Ubi in the hybrid network can
receive data from the downlink common control channel of the wide
area cellular network (for example, for WCDMA network, the downlink
common control channel refers to the Broadcast CHannel (BCH)). When
any terminal has a transmission request, the wide area cellular
network is selected in priority for transmission, and when the wide
area cellular network cannot guarantee the quality of service of
the transmission thereof, the transmission will be relayed to the
wide area cellular network through the surrounding gateway nodes by
using the wireless distributed network.
[0046] FIG. 3 is a schematic diagram of the Downlink Common Control
CHannel (DCCCH) of the wide area cellular network according the
first embodiment of the present invention. As shown in FIG. 3, the
downlink common control channel DCCCH is divided into a plurality
of time units a in time axis, which are called as slots, and
sequential N+1 slots form a frame. The first N slots of each frame
is used for transmitting common control information of the base
station BS, such as broadcast information, paging messages,
synchronization and pilot information and so on. The N+1th slot, in
which the base station does not transmit any information, is
dedicated for carrying relay transmission requests from the
wireless distributed network, and is therefore called as a relay
request slot.
[0047] FIG. 4 shows block diagrams of respective nodes in the
hybrid network. FIG. 4(a) is a block diagram of the gateway
apparatus supporting communications in two networks in the hybrid
network according to the first embodiment of the present
invention.
[0048] As shown in FIG. 4(a), the gateway apparatus of the present
invention includes a transmission storage unit 410 for storing
packets to be transmitted; a wide area network transmission unit
415 for transmitting signals in the wide area network; a wide area
reception unit 416 for receiving signals from the wide area
network; a distributed network transmission unit 417 for
transmitting signals in the distributed network; a distributed
network reception unit 418 for receiving signals from the
distributed network, a detection unit 412 for detecting signals
received by the wide area reception unit 416 on the downlink common
control channel, and detecting the type of current slot on the
downlink common control channel, that is, whether it is a relay
request slot or not; an access determination unit 411 for receiving
result of the detection from the detection unit 412, and
determining a network to be accessed currently; a transmission
control unit 413 for receiving results from the access
determination unit 411 and the detection unit 412, and controlling
the transmission and reception of signals in the distributed
network; and a delay unit 414 for receiving an instruction from the
transmission control unit 413 and delaying.
[0049] When there is a packet to be transmitted in the transmission
storage unit 410 of the gateway apparatus, the access determination
unit 411 directs access between the gateway apparatus and the wide
area network and performs traffic transmission in the wide area
network through the wide area network transmission unit 415. When
the detection unit 412 detects that a signaling is transmitted on
the current relay request slot, the access determination unit 411
instructs to access the gateway apparatus to the distributed
network and enables the transmission control unit 413.
[0050] When the access determination unit 411 directs access to the
distributed network, the transmission control unit 413 starts the
delay unit 414 to perform a back-off operation, and after a certain
period of back-off, transmits a reply packet RPL through the
distributed network transmission unit 417. After accessing to the
distributed network, when signals received by the distributed
network reception unit 418 indicates that a selection packet SLT
directed to the present gateway apparatus is received, the
transmission control unit 413 instructs the distributed network
transmission unit 417 to transmit a permit packet PMT. When signals
received by the distributed network reception unit 418 indicate
that a data packet is received, the transmission control unit 413
instructs the distributed network transmission unit 417 to transmit
an acknowledgement packet ACK. After the transmission of the
acknowledgement packet is completed, the access determination unit
411 directs to access to the wide area network and transmits to the
base station BS the data packet received from the wireless
distributed network.
[0051] FIG. 4(b) is a block diagram of the wireless terminal having
transmission capability in the distributed network according to the
first embodiment of the present invention. As shown in FIG. 4(b),
the wireless terminal of the present embodiment includes a
transmission storage unit 420 for storing packets to be
transmitted; a distributed network transmission unit 427 for
transmitting signals in the distributed network; a distributed
network reception unit 428 for receiving signals from the
distributed network; a DCCCH transmission unit 425 for transmitting
a relay request signal on the downlink common control channel of
the wide area network; a DCCCH reception unit 426 for receiving
signals from the downlink common control channel of the wide area
network; a detection unit 422 for detecting the signals received by
the DCCCH reception unit 426 on the downlink common control
channel, and detecting current slot type on the downlink common
control channel, that is, whether it is a relay request slot or
not; an access determination unit 421 for receiving signals from
the detection unit 422, and determining a network to be accessed
currently; a transmission control unit 423 for receiving results
from the access determination unit 421 and the detection unit 422,
controlling the transmission and reception of signals in the
distributed network, and clocking; and a delay unit 424 for
receiving an instruction from the transmission control unit 423 and
delaying.
[0052] When there is a packet to be transmitted in the transmission
storage unit 420 of the wireless terminal, the access determination
unit 421 directs to access to the DCCCH channel, and transmits a
relay request signal through the DCCCH transmission unit 425 on the
relay request slot detected by the detection unit 422. After the
transmission of the relay request signal is completed, the access
determination unit 421 directs to access to the distributed network
and enables the transmission control unit 423.
[0053] When the access determination unit 421 directs to access to
the distributed network, the transmission control unit 423 starts
clocking, and receives signals through the distributed network
reception unit 428 within a reception threshold time. When the
reception threshold time is reached, if a reply packet RPL is
correctly received, the received signal is analyzed, and the
distributed network transmission unit 427 is instructed to transmit
a selection packet SLT. If no packet is received, then the delay
unit 424 is enabled. When the distributed network reception unit
428 receives a permit packet PMT, a data packet is transmitted.
Further, when the distributed network reception unit 428
successfully receives an acknowledgement packet ACK, the access
determination unit 421 is instructed to stop the access to the
distributed network.
[0054] Additionally, the gateway apparatus capable of supporting
communications in two networks may also be used as a wireless
terminal Ubi, for example, in a case where the measured DCCCH
signals indicates that current channel conditions cannot fulfill
the QoS requirements of the transmission thereof or this node
cannot directly communicate with the base station BS. In this case,
the block diagram of the gateway apparatus is same as FIG. 4(b),
expect for that it is provided with the wide area network
transmission unit 415 and the wide area reception unit 416 which
will not function now.
[0055] FIG. 5 is a schematic diagram for accessing when the
wireless terminal has a transmission request in the hybrid network
of the present invention. At step S501, the wireless terminal in
the hybrid network is in an idle state and only senses the downlink
common control channel (DCCCH) from the wide area network through
the DCCCH reception unit 426. At step S502, when the wireless
terminal has a transmission request, it will be determined whether
it can perform traffic transmission directly with the base station
BS or not according to its node functionality and the sensed
channel conditions of the DCCCH.
[0056] If it can directly connect with and communicate with the
base station BS, then the wireless terminal may be used as a
gateway (GW) node. At step S506, the wireless terminal is directly
accessed to the wide area network to perform traffic transmissions.
If the wireless terminal cannot establish a direct connection with
the base station BS and communicate therewith, then it indicates
that the wireless terminal is a Ubi node (a wireless terminal only
used for communication). Thereafter, at step S503, the detection
unit 422 detects whether the slot on the DCCCH is a Relay Request
slot (RRq slot) or not.
[0057] If the slot is a relay request slot, then at step S504, a
Relay Request signal (RRq signal) is transmitted on the relay
request slot by the DCCCH transmission unit 425. Thereafter, at
step S505, the access determination unit 421 directs to access the
wireless terminal to the wireless distributed network for preparing
for traffic transmission. On the contrary, if the slot is not a
relay request slot, then the flow proceeds to step S501, the
downlink common control channel is subsequently sensed.
[0058] FIG. 6 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the first embodiment of the present
invention. At step S601, the wireless terminal (Ubi node) in the
hybrid network senses the DCCCH channel all the time. At step S602,
it is determined whether transmission request signal is sensed. At
step S603, when the wireless terminal Ubi has a transmission
request, a relay request signal is transmitted on the relay request
slot of the downlink common control channel, and when the
transmission is completed, the distributed network transmission
unit 427 and the distributed network reception unit 428 for the
wireless distributed network are enabled to sense a wireless
distributed network channel, that is, step S604.
[0059] At step S605, if the sensing period has reached the
threshold time, then at step S606, it is detected whether a reply
packet RPL is received within this period. If it is not received,
then at step S611, the contention window is enlarged, and after
delaying a certain period, the DCCCH is subsequently sensed and the
relay request signal is retransmitted. If the reply packet RPL is
received, then at step S607, one relay node (gateway apparatus) is
selected from multiple reply packets RPL, and a selection packet
SLT is transmitted thereto. After the transmission of the selection
packet SLT is completed, it is determined at step S608 whether a
permit packet PMT is received or not. If the permit packet PMT is
received, then at step S609, a data packet is transmitted, and then
at step S610, it is determined whether an acknowledgement packet
ACK is received or not. After the acknowledgement packet ACK is
received, the transmission is terminated, and at step S612, it
exits from the distributed network. Otherwise, at step S611, the
contention window is enlarged, and after delaying a certain period,
the relay request is retransmitted.
[0060] FIG. 7 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-point transmission with the wireless terminal
in the hybrid network according to the first embodiment of the
present invention. As shown in FIG. 7, at step S701, the gateway
apparatus in the hybrid network senses the DCCCH channel all the
time. At step S702, it is determined whether the detection unit 412
detects a relay request signal or not. When the detection unit 412
detects that there is a relay request signal in the relay request
slot on the DCCCH channel, at step S703, the delay unit 414 delays
a random period. Thereafter, at step S704, the wireless distributed
network transmission unit 417 is enabled to transmit a reply packet
RPL.
[0061] If the transmission of the replay packet RPL is completed,
at step S705, it is determined whether a selection packet SLT is
received from the surrounding wireless terminals. At step S706, if
a selection packet SLT directed to the gateway apparatus is
received, then at step S706, a permit packet PMT is transmitted. On
the contrary, it exits from the distributed network and only senses
the DCCCH channel. After the transmission of the permit packet PMT
is completed, at step S707, it is determined whether a data packet
is received. If the data packet is successfully received, then at
step S708, an acknowledgement packet ACK is transmitted, and
thereafter it exits from the distributed network at step S709, and
at step S710, begins to access the transmission channel in the wide
area network to transmit the data packet.
[0062] FIG. 8 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a
point-to-point connection with the gateway apparatus and then
transmits data, and the gateway apparatus relays the packets to the
wide area network according to the first embodiment of the present
invention.
[0063] The gateway apparatus GW1 and the gateway apparatus GW2
sense the downlink common control channel of the wide area network
all the time. When the wireless terminal Ubi has a request for
transmitting data packets through the gateway apparatus, it
transmits the relay request signal on the relay request slot of the
DCCCH at the time instant t.sub.1, through the DCCCH transmission
unit 425.
[0064] At the time instant t.sub.2, the wireless terminal Ubi
finishes the transmission and enables the wireless distributed
network transmission unit 427 and the distributed network reception
unit 428 for preparing for the reception of signals, and clocks by
the transmission control unit 423. The gateway apparatuses GW1 and
GW2 which are around the wireless terminal Ubi and detect the relay
request signal on the DCCCH enter into the back-off procedures at
the time instant t.sub.2, delay a random period, and at the time
instants t.sub.3 and t.sub.4 after the delaying, enables the
wireless distributed network transmission unit 417 and the
distributed network reception unit 418 to transmit the reply packet
RPL.
[0065] When the transmission control unit 423 indicates that the
reception threshold time is reached, that is, at the time instant
t.sub.5, the wireless terminal Ubi detects whether the reply packet
RPL is received or not by the detection unit 422. Information of
channels between the current gateway apparatus to the base station
BS and the wireless terminal is contained in the reply packet RPL.
Thereafter, the conditions of channels with the BS indicated in the
received reply packets RPL are compared, and the gateway apparatus
GW2 which has the best condition of channel with the BS and needs
the lowest transmission power for the direct communication with the
BS is selected as the relay apparatus of the wireless terminal Ubi.
Thereafter, at the time instant t.sub.5, the selection packet SLT
that contains an address of the selected gateway apparatus, for
example an address of the gateway apparatus GW2, is transmitted by
the wireless distributed network transmission unit 427. For
example, the wireless terminal Ubi selects the gateway apparatus
with the largest signal to interference and noise ratio (SINR) or
the nearest distance according to power measurements in order to
determine the most appropriate relay gateway.
[0066] At the time instant t.sub.6, when the gateway apparatus GW1
receives the selection packet SLT from the wireless terminal Ubi,
it detects that the packet is not a packet directed thereto and
thus turns off the distributed network transmission unit 417 and
the distributed network reception unit 418 and enters into the idle
state. The gateway apparatus GW2 receives the selection packet SLT
from the wireless terminal Ubi, and detects that the packet is a
packet directed thereto. Then, the gateway apparatus GW2 transmits
the permit packet PMT at the time instant t.sub.7 by the
distributed network transmission unit 417 to indicate that it is
ready to receive and relay the data packet from the wireless
terminal Ubi.
[0067] At the time instant t.sub.8, the wireless terminal Ubi
receives the permit packet PMT from the gateway apparatus GW2. At
the time instant t.sub.9, the wireless terminal Ubi transmits, to
the gateway apparatus GW2, the data packet to be transmitted, and
at the time instant t.sub.10 after completing the transmission of
the data packet, terminates the transmission.
[0068] At the time instant t.sub.10, the gateway apparatus GW2
successfully receives the data packet from the wireless terminal
Ubi. At the time instant t.sub.11, the acknowledgement packet ACK
is transmitted, and at the time instant t.sub.12 after completing
the transmission of the acknowledgement packet ACK, the distributed
network transmission unit 417 and the distributed network reception
unit 418 are turned to prepare for the data transmission in the
wide area network.
[0069] At the time instant t.sub.13, the gateway apparatus GW2
successfully connects to the transmission channel of the wide area
network and begins to transmit the data packet received from the
wireless terminal Ubi.
[0070] FIG. 9 is a timing diagram of respective nodes in a case
where the wireless terminal performs retransmission when no reply
signal is received in a reception threshold time according to the
first embodiment of the present invention.
[0071] When the wireless terminal Ubi has a transmission request,
it transmits the relay request signal on the relay request slot of
the DCCCH at the time instant t.sub.1. Thereafter, at the time
instant t.sub.2, the transmission is completed, and the wireless
distributed network transmission unit 427 and the distributed
network reception unit 428 are enabled to prepare for the signal
reception and the transmission control unit 423 begins clocking. At
the time instant t.sub.5 at which the reception threshold time is
reached, the wireless terminal Ubi detects no reply packet and then
enlarges its contention window and delays a random period within
the contention window.
[0072] At the time instant t.sub.6, which is the end of the delayed
interval the wireless terminal Ubi retransmits the relay request
signal on the first relay request slot on the DCCCH detected after
that time instant, that is, at the time instant t.sub.9.
[0073] FIG. 10 is a timing diagram of respective nodes in a case
where multiple wireless terminals transmit relay request signals in
one and the same relay request slot according the first embodiment
of the present invention.
[0074] As shown in FIG. 10, at the time instant t.sub.1, the
wireless terminals Ubi1 and Ubi2 simultaneously transmit the relay
request signals on the detected relay request slot of the DCCCH.
The gateway apparatus GW2 senses that there is non-noise signal in
the relay request slot on the DCCCH, and thus delays a certain
period. Thereafter, at the time instant t.sub.3 after the end of
the back-off, the wireless distributed network transmission unit
417 and the distributed network reception unit 418 are enabled to
transmit the reply packet RPL.
[0075] The wireless terminals Ubi1 and Ubi2 only receive the reply
packet RPL from the gateway apparatus GW2 within the reception
threshold time, and thus select the gateway apparatus GW2 as the
respective relay apparatuses, that is, at the time instant t.sub.4,
simultaneously transmit the selection packets SLT directed to the
gateway apparatus GW2.
[0076] At the time instant t.sub.5, the gateway apparatus GW2
detects the collision and thus exits from the distributed network.
The wireless terminals Ubi1 and Ubi2 do not receive the permit
packet PMT within a certain period after transmitting the SLT, then
consider it as a transmission failure, increase the contention
windows, enter into the back-off procedures, and after the end of
the back-off, subsequently detect the relay request slot on the
DCCCH.
[0077] The wireless terminal Ubi1 retransmits the relay request
signal on the first relay request slot on the DCCCH detected after
the end of the back-off procedure, that is, at the time instant
t.sub.6. The wireless terminal Ubi2 retransmits the relay request
signal on the first relay request slot on the DCCCH detected after
the end of the back-off procedure, that is, at the time instant
t.sub.8.
[0078] In this example, although the relay request signals from
multiple wireless terminals Ubi collide on one and the same relay
request slot on the DCCCH, the gateway apparatus GW2 enables the
distributed network transmission unit 417 and the distributed
network reception unit 418 only if the power level on this slot is
detected to be larger than the noise power, and then prepares for
transmitting the reply packet RPL, and thus will not influence on
the reception of the relay request signals from the wireless
terminals Ubi. As another example, the gateway apparatus GW2
transmits the reply signal to the surrounding wireless terminals
Ubi once detecting a high level at the relay request slot.
[0079] As above discussed, according to the first embodiment of the
present invention, in a hybrid network of a wide area network and a
wireless distributed network, a dedicated slot on the downlink
common control channel of the wide area network is allocated for
carrying the relay request signals. When the wireless terminal
cannot directly communicate with the base station of the wide area
network, it transmits the relay request signal on the relay request
slot by sensing the downlink common control channel. The gateway
apparatuses which are around the wireless terminal and detect the
relay request signal on the relay request slot of the downlink
common control channel access to the wireless distributed network
at this time to transmit the reply packets.
[0080] Therefore, by transmitting the relay request signal on the
downlink common control channel, the gateway apparatus need not
sense signals from two networks in the idle state, but only senses
the downlink common control channel of the wide area network. If
necessary, the gateway apparatus enables the wireless distributed
network transmission unit and the distributed network reception
unit for relay, so that the power consumption of the gateway
apparatus used for unnecessarily sensing the wireless distributed
network is reduced and thus the standby time of the gateway node is
increased.
[0081] Although the operations performed in a case where the
gateway apparatus and the wireless terminal establish a
point-to-point connection according to the first embodiment of the
present invention has been described, the present invention is not
limited thereto. In the present invention, one gateway apparatus
may simultaneously establish connections to multiple wireless
terminals, that is to say, establish a point-to-multipoint
connection, so that relay the data transmissions for the multiple
wireless terminals in a polling manner.
[0082] FIG. 11 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-multipoint transmission with multiple wireless terminals
in the hybrid network according to the first embodiment of the
present invention.
[0083] It should be noted that the differences between the steps of
FIG. 11 and the steps of FIG. 6 start from the reception of the
reply signal, the description about the preceding steps S1101-S1105
is similar to that for FIG. 6. Therefore, the repeated description
about steps S1101-S1105 is omitted.
[0084] At step S1106, the wireless terminals Ubi1 and Ubi2 receive
the reply packet from the gateway apparatus GW. Then, at step
S1107, the wireless terminals transmit the selection packets SLT
after certain periods of back-off. If the wireless terminals
receive acknowledgement poll packets ACK+Poll after the threshold
time, then they sequentially transmit the data packets to the
gateway apparatus transmitting the poll packets at step S1109. At
step S1110, if the acknowledgement packets ACK are received after
transmitting the data packet, the transmission is terminated, and
at step S1112, they exit from the distributed network. Otherwise,
at step S1111, the contention windows are enlarged, and the relay
requests are retransmitted after delaying certain periods.
[0085] FIG. 12 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-multipoint transmission with multiple wireless
terminals in the hybrid network according to the first embodiment
of the present invention.
[0086] Also, it should be noted that the differences between the
steps of FIG. 12 and the steps of FIG. 7 start from the
transmission of the reply packet, the description about the
preceding steps S1201-S1203 is similar to that for FIG. 7.
Therefore, the repeated description about steps S1201-S1203 is
omitted.
[0087] At step S1204, the gateway apparatus GW transmits the reply
packet RPL. After the transmission of the reply packet RPL is
completed, at step S1205, the gateway apparatus GW senses the
channel of the wireless distributed network, and then at step
S1206, determines whether the threshold time is reached. If the
threshold time is not reached, then the channel of the wireless
distributed network is continuously sensed. If the threshold time
is reached, at step S1207, it is detected at the end of the
threshold time whether the selection packet is successfully
received or not. If at the end of the threshold time, the selection
packets SLT1 and SLT2 from multiple wireless terminals Ubi1 and
Ubi2 are received, then at step S1208, the gateway apparatus GW
transmits an acknowledgement poll packet ACK+poll1 to one of the
wireless terminals for example Ubi1 to allow it to transmit to the
gateway apparatus GW the data to be relayed. At step S1209, if the
gateway apparatus GW successfully receives the data packet DATA1
from the polled wireless terminal Ubi1 by the distributed network
reception unit 418, then at step S1210, it is determined whether
the polling is finished. When there is still an un-polled wireless
terminal, the flow returns to step S1208 to transmit an
acknowledgement poll packet ACK+poll2 to poll the next wireless
terminal Ubi2, and the same operations as above are performed. If
it is determined at step S1210, that the polling is finished, the
acknowledgement packet ACK is then transmitted to the wireless
terminal Ubi2 at step S1211. Thereafter, at step S1212, it exits
from the wireless distributed network after completing the
transmission of the acknowledgement packet ACK, and at step S1213,
the gateway apparatus GW transfers the data packets from the
multiple wireless terminals Ubi1 and Ubi2 received from the
wireless distributed network, to the base station BS in the wide
area network.
[0088] FIG. 13 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a connection
with the gateway apparatus and then transmits data in the
point-to-multipoint scenario according to the first embodiment of
the present invention.
[0089] Also, since FIG. 13 is similar to FIG. 8 except that FIG. 13
shows a case where two wireless terminals Ubi1 and Ubi2 establish
connections to one gateway apparatus GW and then the data are
transferred, the description about the operations before the time
instant t.sub.4 is omitted. At the time instant t.sub.4, the
wireless terminals Ubi1 and Ubi2 both receives the reply packet RPL
from the gateway apparatus GW and enter into the back-off
procedures. The wireless terminals Ubi1 and Ubi2 respectively
transmit the selection packets SLT1 and SLT2 after the end of the
back-off procedures, indicating that they both select the gateway
apparatus GW as the gateway node for relay.
[0090] The gateway apparatus GW detects that multiple selection
packets SLT1 and SLT2 are received within the reception threshold
time starting from the transmission of the reply packet, and after
the end of the reception threshold time, at the time instant
t.sub.7, transmits the acknowledgement poll packet ACK+poll1 to the
wireless terminal Ubi1 to allow the wireless terminal Ubi1 to
transmit its data packet to be relayed. The wireless terminal Ubi1
transmits the data packet DATA1 at the time instant t.sub.8, after
receiving the acknowledgement poll packet ACK+poll1 directed
thereto.
[0091] After successfully receiving the data packet from the
wireless terminal Ubi1, the gateway apparatus GW detects that there
is still an un-polled wireless terminal Ubi2, and then at the time
instant t.sub.9, transmits the acknowledgement poll packet
ACK+poll2 to the wireless terminal Ubi2. At the time instant
t.sub.10, the wireless terminal Ubi2 transmits the data packet
DATA2 after receiving the acknowledgement poll packet directed
thereto. After receiving the DATA2, the gateway apparatus GW
detects that all the wireless terminals have already been polled,
and then at the time instant t.sub.11, transmits the
acknowledgement packet ACK to the wireless terminal Ubi2.
[0092] Thereafter, the gateway apparatus GW exits from the wireless
distributed network, and at the time instant t.sub.12, transfers to
the base station BS in the wide area network, the data packets
DATA1 and DATA2 from the wireless terminals Ubi1 and Ubi2 received
from the wireless distributed network.
[0093] Thus, in the first embodiment of the present invention,
after accessing the wireless distributed network, the gateway
apparatus may perform transmissions with multiple surrounding
wireless terminals in a polling manner.
The Second Embodiment
[0094] FIG. 14 is a timing diagram of the channels related with the
second embodiment of the present invention. In the second
embodiment, a synchronization signaling for synchronizing with a
slot in the downlink common control channel is periodically
transmitted in the transmission frequency band of a wireless
distributed network by a base station BS of a wide area network.
The wireless terminal Ubi transmits a relay request signal when
receiving the synchronization signaling, and a gateway apparatus GW
starts to access the distributed network corresponding to the
synchronization signaling in order to receive the relay request
signal from the wireless terminal Ubi. For example, the gateway
apparatus GW starts to access the distributed network at a time
instant corresponding to the synchronization signaling by sensing
the downlink common control channel of the wide area network.
[0095] The base station transmits control information from the wide
area network through the downlink common control channel of the
wide area network, such as a synchronization message, a paging
message etc. Meanwhile, the base station periodically transmits the
synchronization signaling on the frequency band used in the
wireless distributed network, the synchronization signaling being
synchronous with slot in the downlink common control channel.
[0096] The gateway apparatus in the hybrid network receives the
signals on the downlink common control channel of the wide area
network all the time, and enables wireless distributed network
transmission unit and the distributed network reception unit at the
starting time of each synchronization signaling with a period same
as the synchronization signaling, detects whether there are data or
request to transmit signal, and when detecting the above signal,
communicates by the wireless distributed network transmission unit
and the distributed network reception unit.
[0097] The wireless terminal Ubi in the hybrid network receives the
synchronization signaling from the base station, and when having a
traffic transmission request, transmits the relay request signal
after receiving the synchronization signaling.
[0098] FIG. 15 shows block diagrams of the structures of the
gateway apparatus and the wireless terminal in the hybrid network
according to the second embodiment of the present invention. FIG.
15(a) is a block diagram of the structure of the gateway apparatus
supporting communications in two networks in the hybrid
network.
[0099] As shown in FIG. 15(a), the gateway apparatus of the second
embodiment includes a transmission storage unit 1511 for storing
packets to be transmitted; a wide area network transmission unit
1515 for transmitting signals in the wide area network; a wide area
reception unit 1516 for receiving signals from the wide area
network; a distributed network transmission unit 1517 for
transmitting signals in the distributed network; a distributed
network reception unit 1518 for receiving signals from the
distributed network; a timer unit 1512 for detecting whether the
current time is an integer multiple of a periodic time, and
periodically enabling a sensing unit 1513 to sense a channel of the
distributed network; sensing unit 1513 for sensing the channel of
the distributed network at the enabling time instant instructed by
the timer unit 1512; a transmission control unit 1514 for
controlling transmission and reception of signals in the
distributed network according to signals received from the sensing
unit 1513; and a delay unit 1519 for receiving an instruction from
the transmission control unit 1514 and delaying.
[0100] When the sensing unit 1513 detects in a sensing time
interval that there is a data transmission in the wireless
distributed network, it instructs the transmission control unit
1514 to communicate with the surrounding wireless terminals Ubi
according to a communication protocol of the wireless distributed
network. When the sensing unit 1513 specifies that there is no
signal detected in the sensing time interval, no operation is
performed.
[0101] FIG. 15(b) is a block diagram of the wireless terminal Ubi
only supporting transmissions in the distributed network in the
hybrid network. As shown in FIG. 15(b), the functional modules of
the wireless terminal according to the present embodiment are a
part of the gateway apparatus shown in FIG. 15(a). The wireless
terminal of the second embodiment includes a transmission storage
unit 1521 for storing packets to be transmitted; a distributed
network transmission unit 1527 for transmitting signals in the
distributed network; a distributed network reception unit 1528 for
receiving signals from the distributed network; a transmission
control unit 1524 for controlling transmission and reception of
signals in the distributed network, and clocking; and a delay unit
1529 for receiving an instruction from the transmission control
unit 1524 and delaying.
[0102] FIG. 16 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the second embodiment of the present
invention.
[0103] At step S1601, the wireless terminal Ubi in the hybrid
network is in an idle state and periodically senses synchronization
signaling from the base station. This is because the
synchronization signaling information transmitted by the base
station is transmitted on the frequency band with which the
wireless distributed network operates. At step S1602, it is
determined whether there is a traffic transmission request or not,
that is, whether there are data and signals to be transmitted in
the transmission storage unit 1521 or not. When there is the
traffic transmission request, at step S1603, the transmission
control unit 1524 determines whether a synchronization signaling is
received or not. If not, then at step S1604, the wireless terminal
Ubi waits for the next synchronization signaling. If the
synchronization signaling is received, then at step S1605, the
distributed network transmission unit 1527 transmits a relay
request signal at the ending instant of the synchronization
signaling.
[0104] Thereafter, at step S1606, the wireless distributed network
transmission unit 1527 and reception unit 1528 sense the wireless
distributed network channel. At step S1607, if the sensed time
reaches a threshold time, then at step S1608, it is detected
whether a reply packet RPL is received within this period or not.
If not, then at step S1610, the contention window is enlarged, the
channel is sensed after delaying a certain period, and the relay
request signal is retransmitted.
[0105] If the reply packets RPL are received, then at step S1609,
the transmission control unit 1524 selects one relay node (gateway
apparatus) from the plurality of received replay packets, and
transmits a selection packet SLT to the selected node. After the
transmission of the selection packet SLT is completed, it is
determined at step S1611 whether a permit packet PMT is received or
not. If the permit packet PMT is received, then a data packet is
transmitted at step S1612.
[0106] Thereafter, at step S1613, the transmission control unit
1524 determines whether an acknowledgement packet ACK is received
or not. After the acknowledgement packet ACK is received, the flow
returns to step S1601, and the channel is subsequently sensed for
next transmission. Otherwise, at step S1610, the contention window
is enlarged, and the flow returns to step S1601 after delaying a
certain period, and the above processes are repeated.
[0107] FIG. 17 is a detail flowchart of operation on the gateway
apparatus side in a case where the gateway apparatus performs a
point-to-point transmission with the wireless terminal in the
hybrid network according to the second embodiment of the present
invention.
[0108] At step S1701, the gateway apparatus GW in the hybrid
network is in an idle state and only senses signals of the downlink
common control channel of the wide area network from a base
station. At step S1702, the timer unit 1512 determines whether
current time is an integral multiple of the period of the
synchronization signaling or not. At step S1703, in a case where
the current time is an integral multiple of the period (here, the
period refers to the transmission period of the synchronization
signaling), the transmission control unit 1514 enables the wireless
distributed network reception unit 1518 and senses the channel. At
step S1704, it is determined whether there are signals to be
transmitted. When it is detected that there are data or a request
to transmit signals on the channel, at step S1705, the wireless
distributed network transmission unit 1517 and the distributed
network reception unit 1518 are enabled to access the wireless
distributed network, and the delay unit 1519 is enabled for
delaying a certain period. Thereafter, at step S1706, a reply
packet RPL is transmitted by the wireless distributed network
transmission unit 1517 in the wireless distributed network.
[0109] If the transmission of the reply packet RPL is completed, it
is determined at step S1707 whether a selection packet SLT is
received from surrounding wireless terminals. At step S1708, if the
selection packet SLT directed to the gateway apparatus is received,
then a permit packet PMT is transmitted.
[0110] If no signal is detected in a certain time interval, then
the wireless distributed network transmission unit 1517 and the
distributed network reception unit 1518 are turned off, and only
the DCCCH is sensed. After the transmission of the permit packet
PMT is completed, it is determined at step S1709 whether a data
packet is received. If the data packet is successfully received,
then an acknowledgement packet ACK is transmitted at step S1710,
and then at step S1711, it exits from the distributed network, and
at step S1712, it begins to access the transmission channel in the
wide area network for transmitting the data packet.
[0111] FIG. 18 is a timing diagram of respective nodes according to
the second embodiment of the present invention. For illustration,
only the timing relationship between one gateway apparatus GW and
the wireless terminal Ubi is given. However, there are always a
plurality of gateway apparatuses around the wireless terminal Ubi,
for example, gateway apparatuses GW1 and GW2. The base station
transmits the synchronization signaling in the wireless distributed
network at the time instants t.sub.1, (T+t.sub.1), . . . with a
period of T. At the same time, the wireless terminal Ubi receives
the synchronization signaling within the wireless distributed
network with the same period. The gateway apparatuses GW1 and GW2
enable the wireless distributed network transmission unit and the
distributed network reception unit with the same period to sense
the channel. The wireless terminal Ubi generates the traffic
transmission request within a time interval from t.sub.1 to
(T+t.sub.1), that is, there are data and signals to be transmitted
in the transmission storage unit 1521, and then after receiving the
synchronization signaling at the time instant (T+t.sub.1),
transmits the relay request packet by the wireless distributed
network transmission unit 1527.
[0112] Since at the time instant (T+t.sub.1), the gateway
apparatuses GW1 and GW2 are both sensing signals from the DCCCH of
the wide area network and the channel of the wireless distributed
network, they receives the relay request signal from the wireless
terminal Ubi. After the reception of the signals is received, the
delay units 1519 are enabled for entering into the back-off
procedures to randomly delaying a certain period. At the ending
instant of the delay, the wireless distributed network transmission
unit 1517 and the distributed network reception unit 1518 are
enabled to transmit the reply packet RPL.
[0113] When the transmission control unit 1514 specifies that the
reception threshold time is reached, the wireless terminal Ubi
determines whether the reply packet RPL is received or not, the
reply packet RPL containing channel information of the current
gateway apparatus to the base station BS and the wireless terminal.
Thereafter, the conditions of channel to the base station BS
indicated in the received reply packets RPL are compared, and the
gateway apparatus GW2 that has the best condition of channel to the
base station BS and needs the lowest transmission power for the
direct communication with the base station BS is selected as the
relay apparatus of the wireless terminal Ubi. Thereafter, the
selection packet SLT is transmitted by the distributed network
transmission unit 1527 and contains an address of the selected
gateway apparatus, for example an address of the gateway apparatus
GW2. For example, the wireless terminal Ubi selects the gateway
apparatus with the largest signal to interference and noise ratio
(SINR) or the nearest distance according to power measurements in
order to determine the most appropriate relay gateway.
[0114] Next, when the gateway apparatus GW1 receives the selection
packet SLT from the wireless terminal Ubi, it detects that the
packet is not a packet directed thereto and thus turns off the
distributed network transmission unit 1517 and the distributed
network reception unit 1518 and enters into the idle state. The
gateway apparatus GW2 receives the selection packet SLT from the
wireless terminal Ubi, and detects that the packet is a packet
directed thereto. Then, the gateway apparatus GW2 transmits the
permit packet PMT by the distributed network transmission unit 1517
to indicate that it is ready to receive and relay the data packet
from the wireless terminal Ubi.
[0115] Then, the wireless terminal Ubi receives the permit packet
PMT from the gateway apparatus GW2. The wireless terminal Ubi
transmits to the gateway apparatus GW2 the data packet to be
transmitted by the distributed network transmission unit 1527, and
after completing the transmission of the data packet, terminates
the transmission.
[0116] Next, the gateway apparatus GW2 successfully receives the
data packet from the wireless terminal Ubi by the distributed
network reception unit 1518 so that the acknowledgement packet ACK
is transmitted, and when completing the transmission of the
acknowledgement packet ACK, turns off the distributed network
transmission unit 1527 and the distributed network reception unit
1528 for preparing for the data transmission in the wide area
network.
[0117] The gateway apparatus GW2 successfully connects to the
transmission channel of the wide area network and begins to
transmit the data packet received from the wireless terminal
Ubi.
[0118] Although the operations performed in a case where the
gateway apparatus and the wireless terminal establish a
point-to-point connection according to the second embodiment of the
present invention have been described, the present invention is not
limited thereto. In the present invention, one gateway apparatus
may simultaneously establish connections to multiple wireless
terminals, that is to say, establish a point-to-multipoint
connection in order to relay the data transmissions for the
multiple wireless terminals in a polling manner.
[0119] FIG. 19 is a detail flowchart of operation on the wireless
terminal side in a case where the gateway apparatus performs a
point-to-multipoint transmission with multiple wireless terminals
in the hybrid network according to the second embodiment of the
present invention.
[0120] It should be noted that the differences between FIG. 19 and
FIG. 16 start from the reception of the reply signal, the
description about the preceding steps S1901-S1907 is similar to
that for FIG. 6. Therefore, the repeated description about steps
S1901-S1907 is omitted.
[0121] At step S1908, the wireless terminals receive the reply
packet from the gateway apparatus GW. Then, at step S1909, the
wireless terminals enable the delay units 1529 to enter into the
back-off procedures, and transmit the selection packets SLT after
certain periods of back-off. At step S1911, it is determined
whether acknowledgement poll packets ACK+poll are received from the
gateway apparatus GW. If the wireless terminals receive
acknowledgement poll packets ACK+poll after the threshold time,
then they sequentially transmit the data packets to the gateway
apparatus which transmitted the poll packets at step S1912.
[0122] Thereafter, at step S1913, the transmission control unit
1524 determines whether the acknowledgment packets ACK are
received. After the acknowledgement packets ACK are received, the
flow returns to step S1901, and the channel is subsequently sensed
for the next transmission. Otherwise, at step S1910, the contention
window is enlarged, the flow returns to step S1901 after delaying
certain periods, and the above processes are repeated.
[0123] FIG. 20 is a detail flowchart of the relaying operation on
the gateway apparatus side in a case where the gateway apparatus
performs a point-to-multipoint transmission with multiple wireless
terminals in the hybrid network according to the second embodiment
of the present invention.
[0124] Also, it should be noted that the differences between FIG.
20 and FIG. 17 start from the transmission of the reply packet, the
description about the preceding steps S2001-S2005 is similar to
that for FIG. 17. Therefore, the repeated description about steps
S2001-S2005 is omitted.
[0125] At step S2006, the gateway apparatus GW transmits the reply
packet RPL. After the transmission of the reply packet RPL is
completed, at step S2007, it is detected whether a selection packet
is successfully received. If the selection packets SLT1 and SLT2
from multiple wireless terminals Ubi1 and Ubi2 are successfully
received, then at step S2008, the gateway apparatus GW transmits an
acknowledgement poll packet ACK+poll1 to one of the wireless
terminals for example Ubi1 to allow it to transmit to the gateway
apparatus GW the data to be relayed. At step S2009, if the gateway
apparatus GW successfully receives the data packet DATA1 from the
polled wireless terminal Ubi1 by the distributed network reception
unit 1518, then at step S2010, it is determined whether the polling
is finished. When there is still an un-polled wireless terminal,
the flow returns to step S2008 to transmit an acknowledgement poll
packet ACK+poll2 to poll the next wireless terminal Ubi2. The same
operations as above are performed. If it is determined at step
S2010 that the polling is finished, the acknowledgement packet ACK
is then transmitted to the wireless terminal Ubi2 at step S2011.
Thereafter, at step S2012, it exits from the wireless distributed
network after completing the transmission of the acknowledgement
packet ACK, and at step S2013, the gateway apparatus GW transfers
the data packets from the multiple wireless terminals Ubi1 and Ubi2
received from the wireless distributed network, to the base station
BS in the wide area network.
[0126] FIG. 21 is a timing diagram of respective nodes in a case
where the wireless terminal successfully establishes a
point-to-multipoint connection with the gateway apparatus and then
transmits data according to the second embodiment of the present
invention.
[0127] Similar to FIG. 18, the base station transmits the
synchronization signaling in the wireless distributed network at
the time instants t.sub.1, (T+t.sub.1), . . . with a period of T.
At the same time, the wireless terminals Ubi1 and Ubi2 receive the
synchronization signaling within the wireless distributed network
with the same period. The gateway apparatus GW enables the wireless
distributed network transmission unit 1517 and the distributed
network reception unit and 1518 with the same period to sense the
channel. The wireless terminals Ubi1 and Ubi2 generate the traffic
transmission requests prior to t.sub.1, that is, there are data and
signals to be transmitted in the transmission storage unit 1521,
and then after receiving the synchronization signaling at the time
instant t.sub.1, respectively transmit the relay request packets
RRq1 and RRq2 by the wireless distributed network transmission
units 1527.
[0128] After receiving the relay request packets RRq1 and RRq2, the
gateway apparatus GW transmits the reply packet RPL to the wireless
terminals Ubi1 and Ubi2. After receiving the replay packet from the
gateway apparatus GW, the wireless terminals Ubi1 and Ubi2 enable
the delay unit 1529 for entering into the back-off procedures.
After delaying certain periods, the wireless terminals Ubi1 and
Ubi2 respectively transmits the selection packet SLT1 and SLT2
indicating that the gateway apparatus GW is selected as relay
gateway apparatuses thereof.
[0129] The gateway apparatus GW detects that multiple selection
packets SLT1 and SLT2 are received within the reception threshold
time starting from the transmission of the reply packet, and after
the end of the reception threshold time, transmits the
acknowledgement poll packet ACK+poll1 to the wireless terminal Ubi1
to allow the wireless terminal Ubi1 to transmit its data packet to
be relayed. The wireless terminal Ubi1 transmits the data packet
DATA1 after receiving the acknowledgement poll packet ACK+poll1
directed thereto.
[0130] After successfully receiving the data packet from the Ubi1,
the gateway apparatus GW detects that there is still an un-polled
wireless terminal Ubi2, and then transmits the acknowledgement poll
packet ACK+poll2 to the wireless terminal Ubi2. The wireless
terminal Ubi2 transmits the data packet DATA2 after receiving the
acknowledgement poll packet directed thereto. After receiving the
DATA2, the gateway apparatus GW detects that all the wireless
terminals have already been polled, and then transmits the
acknowledgement packet ACK to the Ubi2.
[0131] Thereafter, the gateway apparatus GW exits from the wireless
distributed network, and transfers to the base station BS in the
wide area network, the data packets DATA1 and DATA2 from the Ubi1
and Ubi2 received from the wireless distributed network.
[0132] Thus, in the second embodiment of the present invention,
after accessing the wireless distributed network, the gateway
apparatus may perform transmissions with multiple surrounding
wireless terminals in a polling manner.
[0133] In the second embodiment, the synchronization signaling for
synchronizing with the downlink common control channel is regularly
transmitted on the transmission frequency band of the wireless
distributed network by the base station of the wide area network.
After receiving the synchronization signaling, the wireless
terminal Ubi transmits the relay request signal, and the gateway
apparatus only needs to enable the access to the distributed
network at the time instant corresponding to the synchronization
signaling in order to receive the relay request signal from the
wireless terminal Ubi. Therefore, the gateway apparatus only senses
the distributed network intermittently, and thus the power
consumption is reduced, and the serving time of the gateway node is
increased.
[0134] As described above, according to the second embodiment, in
the hybrid network of the wide area network and the wireless
distributed network, the base station has the functionality of
transmitting the synchronization signaling in the wireless
distributed network. The synchronization signaling is kept
synchronous with the downlink common control channel in the wide
area network. The Ubi node in the network is periodically awaken by
receiving the synchronization signaling information from the base
station, and when having the traffic transmission request, begins
to transmit the data or packet request signal after receiving the
synchronization signaling. The gateway node in the network
periodically enables and senses the channel of the wireless
distributed network according to the timing information provided on
the downlink common control channel of the wide area network. When
sensing that there is signal in the wireless distributed network,
communicates with the Ubi node, and when completing the
communication, the gateway node turns off the transceiver means for
the distributed network, and transfers the previously received
packets to the wide area network. In this manner, the gateway node
in the network may conveniently receive the relay request signal
from the single-mode terminal, save its power consumption, and it
is feasible to transmit the synchronization signaling by the base
station.
[0135] In addition, in the first and second embodiments as
described above, although the wide area network transmission unit
and the wide area network reception unit, as well as the
distributed network transmission unit and the distributed network
reception unit are described in a separated form, those skilled in
the art can also integrate them together as one part during
implementation. Similarly, the DCCCH transmission unit and the
DCCCH reception unit, and the distributed network transmission unit
and the distributed network reception unit in the wireless terminal
can also be implemented respectively as one part.
[0136] Although the embodiments of the present invention have been
described, the protection scope of the present invention is not
limited thereto. Those changes or substitutions which can be
realized by those skilled in the art according to the disclosure of
the present invention should be included therein. Consequently, the
protection scope of the present invention is solely defined by the
appended claims.
* * * * *
References